<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Preferred Style Sheet Group</title>
    <link rel="stylesheet" href="sheet1.css" type="text/css" title="Default layout">
    <link rel="stylesheet" href="sheet2.css" type="text/css" title="Default text sizes">
    <link rel="stylesheet" href="sheet3.css" type="text/css" title="Default colors">
</head>
<body>

</body>
</html>